The prime minister arrived at the Yasukuni shrine in a limousine, and walked behind a Shinto priest in traditional robes.

He spent about 10 minutes inside, and left white chrysanthemum flowers, signing the guest book as prime minister.

Yasukuni supporters, including a number of right-wing activists in military fatigues, waved Japanese flags as Mr Koizumi walked past.

But other Japanese were less happy about the visit. On Sunday, more than 1,000 people marched in Tokyo to protest against such trips, and others staged candlelight vigils.

Mr Koizumi also faces the wrath of Japan's regional neighbours, who had previously warned that any more visits to Yasukuni would further damage ties - which have already been frayed by previous visits as well as other disagreements.

"This move... seriously harms the feelings of those victimised by Japanese militarism during World War II," the Chinese Foreign Ministry said on its website.

The visit "will undermine the political basis for ties between China and Japan," the ministry statement said.

South Korea's foreign ministry expressed "deep disappointment and anger" over the visit.

"The Japanese prime minister's visit to the Yasukuni shrine is a total disrespect for the Korean government and people," Foreign Minister Ban Ki-moon is quoted a telling Reuters news agency.

Both South Korea and China have suspended summit meetings with Mr Koizumi since his last visit, in October.

But Mr Koizumi brushed off the criticism, telling reporters that his visit had been "appropriate".

Anti-shrine demonstrators held a vigil in Tokyo

After paying his respects at the shrine, he joined Emperor Akihito to attend a national memorial service in honour of Japan's war dead, where he apologised to the victims of World War II.

"Our country caused huge damage and suffering to a number of countries, particularly people in Asia," Mr Koizumi said at the ceremony.

"On behalf of the Japanese people, I sincerely express condolences to the victims with our deep remorse."

Future visits?

Mr Koizumi has visited the Yasukuni shrine every year since he became prime minister five years ago, but until now he has always stayed away on the highly symbolic 15 August anniversary.

Correspondents say Tuesday's visit was made to fulfil a promise he made while trying to win the leadership of his party five years ago, when he said he would visit the shrine to mark the anniversary.

This was the last year he could honour that promise, as he is due to step down next month.

Attention is now focusing on whether potential contenders to succeed Mr Koizumi will decide to visit the shrine.

The front-runner, Chief Cabinet Secretary Shinzo Abe, has declined to say what he would do - but he has visited in the past.

Leading rival Sadakazu Tanigaki has ruled out a visit and Foreign Minister Taro Aso, another contender, is also thought to be against one.

Public concern over the shrine issue has been increasing, with recent polls suggesting that more than half the Japanese public do not want their next prime minister to continue the visits.